package com.zdp.netty.chapter12.server;

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.DatagramPacket;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.ThreadLocalRandom;


/**
 * @Author zhengdp
 * @Description
 */
public class ChineseProverbServerHandler extends SimpleChannelInboundHandler<DatagramPacket> {

    private static final String[] DICTIONARY = { "只要功夫深，铁棒磨成针。",
            "旧时王谢堂前燕，飞入寻常百姓家。", "洛阳亲友如相问，一片冰心在玉壶。", "一寸光阴一寸金，寸金难买寸光阴。",
            "老骥伏枥，志在千里。烈士暮年，壮心不已!"};

    private String nextQuote() {
        // ThreadLocalRandom:Netty的线程安全随机类
        int quoteId = ThreadLocalRandom.current().nextInt(DICTIONARY.length);
        return DICTIONARY[quoteId];
    }
    @Override
    protected void messageReceived(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        String req = packet.content().toString(CharsetUtil.UTF_8);
        System.out.println(req);
        if ("谚语字典查询？".equals(req)) {
            // DatagramPacket 入参： 1. 发送内容  2.发送地址（IP+端口）
            ctx.writeAndFlush( new DatagramPacket(Unpooled.copiedBuffer("谚语查询结果:" + nextQuote(), CharsetUtil.UTF_8)
                    , packet.sender()));
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
        cause.printStackTrace();
    }
}
